The present invention generally relates to a novel pyridine compound. More particularly, but not by way of limitation, the present invention discloses the pyridine compound employed as a yellow color former.
Recording materials which employ microencapsulated leuco dyes as color formers are now well known in the art. They include carbonless paper, thermal recording papers and recently cylithographic recording materials of the type described in U.S. Pat. No. 4,399,209. In each of these recording materials, it is desirable to use color formers which exhibit high oil solubility in order to obtain high image densities as the color formers are dissolved in oils to microencapsulate them.
Commonly assigned U.S. Pat. No(s). 4,440,836, 4,842,976, 4,600,678 and 4,576,891 describe cylithographic materials which comprise a polyester film base with a layer of light sensitive microcapsules which are sensitive to red, green and blue light, and are incorporated by reference herein. Image-wise exposure of the material to actinic radiation allows for a colored image to be formed.
U.S. Pat. No. 4,908,447 discloses unsymmetrical 2-,6-diphenyl-4-(4-aminophenyl)pyridine compounds useful as dye precursors. Particularly disclosed is 2-(2-methoxyphenyl)-4-(4-dimethylaminophenyl)-6-phenyl pyridine.
U.S. Pat. No. 3,985,376 discloses yellow dye precursors for pressure-sensitive recording material. This patent teaches of symmetrical 4-(4'-aminophenyl)-pyridines. In one embodiment, 4-(4'-dimethylaminophenyl)-2,6-diphenylpyridine is disclosed. U.S. Pat. No. 4,600,678 discloses the use of this precursor in the aforementioned cylithographic materials. In another embodiment, 4-(4'-aminophenyl)-2,6-(4',4'-dimethoxyphenyl)pyridine is disclosed. While the dye precursors described in the aforementioned patents are useful in pressure-sensitive recording systems, there is a need for improvement in their solubility, color, and the ease with which they can be manufactured. There is also a need for dye precursor which aids in obtaining faster film speed and dynamic range in the imaging field. It is therefore desirable that there be a dye precursor which while still retaining good solubility and color, provides increased manufacturing ease.